1, National University of Singapore, Singapore, , Singapore
Thermoelectricity, based on the Seebeck effect, is an alternative for power generation and refrigeration due to its ability to directly convert thermal into electrical energy. Here, we study thermoelectric properties of exfoliated LixMoS2 grown using Chemical Vapour Transport (CVT), where a mixture of 1T' and 2H phases coexist in a single sample due to the 2H to 1T' phase transition induced by Lithium (Li) intercalation. We show that as-fabricated LixMoS2 devices are p-type in nature with high electrical conductivity due to its metallic 1T' phase, and that in-situ thermal annealing of LixMoS2 in vacuum induces a p-type to n-type transition as a result of delithiation. A peak power factor of 18 uW/mK2 is observed in an effective medium of LixMoS2 where reasonable electrical conductivity is maintained by the metallic 1T’ phase and the Seebeck coefficient is controlled by the semiconducting 2H phase. By refining the thermal annealing temperature and annealing time that controls de-lithiation of LixMoS2, we hypothesize that a higher thermoelectric powerfactor can be achieved, showing an additional knob to tune energy dependent scattering in these novel materials.